Manufacture of springs

ABSTRACT

The invention relates to machines and methods for use in forming loops at end portions of coil springs of the type disclosed in U.S. Pat. No. 3,662,788 (U.S. Pat. application No. 33,271) but differing in that tools are provided whereby &#39;&#39;&#39;&#39;German&#39;&#39;&#39;&#39; type loops may be formed. A spring is supported by support means and operated on by three tools which bend a coil of the spring away from the remainder of the spring and permanently set it to form a loop.

I Umted States Patent 1191 1111 3,782,425 Clarke et a1. Jan. 1, 1974 [541 MANUFACTURE OF SPRINGS 3,194,282 7/1965 Bergevin et a1 140 103 19 v 1 1 James Leonard Clarke; 33122;; 2562-? W112??? 1381182 Robe" h r Quarmy, both of 3,662,788 5/1972 Clarke 61 a1. 140/103 y; lp Mic a l tt, 3,705,609 12/1972 Matts et a1 140 103 Leicester, all of England Assignee: The British United Shoe Machinery Company Limited, Leicester, England Filed: Feb. 28, 1972 Appl. No.: 230,014

[52] U.S. Cl. 140/103 [51] int. Cl. B211 35/02 [58] Field of Search 140/102, 102.5, 103

[56] References Cited UNITED STATES PATENTS 2,078,828 4/1937 Baer et a1. 140/103 3,069,024 12/1962 Penny 3,183,944 5/1965 Reddington 140/103 Primary ExaminerCharles W. Lanham Assistant Examiner-E. M. Combs Att0rneyWil1iam R. Evans et a1.

[57] ABSTRACT The invention relates to machines and methods for use in forming loops at end portions of coil springs of the type disclosed in U.S. Pat. No. 3,662,788 (U.S. Pat. application No. 33,271) but differing in that tools are provided whereby German type loops may be formed. A spring is supported by support means and operated on by three tools which bend a coil of the spring away from the remainder of the spring and permanently set it to form a loop.

4 Claims, 8 Drawing Figures MANUFACTURE OF SPRINGS BACKGROUND OF THE INVENTION In the specification filed in pursuance of copending U.S. Pat. application, Ser. No. 33,271 filed Apr. 30, l97l in the names of Clarke et al. now U.S. Pat. No. 3,662,788 are described methods of and machines for use in forming loops at end portions of coil springs, especially loops of the typev known as English side loops. The machines described in said specification comprise support means for supporting a spring with a portion of the spring projecting from the support means, a first tool comprising a first and a second portion movable along parallel paths relative to each other transversely of the support means, the first portion having a leading end portion adapted to be inserted between coils of a spring in the operationof the machine to initially separate them to provide a loop and the second portion having a bending face arranged to intersect during the transverse movement of the second portion a bending face of the leading end portion so that the loop separated by the leading end portion is engaged thereby, and a second tool co-operative with the first tool in the operation of the machine to impart a permanent set to wire of the spring.

The machine of U.S. Pat. No. 3,662,788 forms English side loops also known as cross-over centre loops which are of the form illustrated in FIG. 8 wherein the wire of the spring is bent sharply so that a coil of the spring stands proud of the coil parallel to the axis of the spring and across the centre of the coil. However this machine is unsuitable without modification for forming loops of the type known as German loops" by which term is meant loops of the type shown in FIG. 7 wherein the wire of the spring is bent somewhat less sharply to bend the end coil away from the rest of the coil to form the loop than in cross-over centre" loops as illustratedin FIG. 8.

SUMMARY OF THE INVENTION An object it is this invention is to provide tools which enable the machine to form German type loops on the end portions of coil springs. This object is achieved by providing three tools to replace the tools described in U.S. Pat. No. 3,662,788. The first tool comprises a coil opener which lifts one or more coils of the spring clear of the remainder to provide a loop, the second tool operates to lift the loop further and the third tool presses the wire of the spring against the second tool to give the wire a permanent set. The third tool comprises two spaced apart portions arranged to pass either side of the second tool in the operation of the machine.

Preferably the second tool of the machine slides in a slot in the first tool and moves parallel to the movement of the first tool.

Preferably one of the portions of the third tool has a hooked end portion which engages the loop of the spring in the operation of the machine.

BRIEF DESCRIPTION OF THE INVENTION In the accompanying drawings:

FIG. 1 is a diagrammatic plan view partly in section showing parts of the first illustrative machine in readiness for operating on a spring on which a loop is to be formed;

FIGS. 2 to 4 are views similar to FIG. 1 but showing tools of the first illustrative machine in various stages of their operation in carrying out the first illustrative method; either 4 FIG. 5 is a diagrammatic view from the rear showing the tools of the first illustrative machine at the same stage in carrying out the first illustrative method as they are shown in FIG. 4;

FIG. 6 is a diagrammatic plan view, partly in section of the second illustrative machine showing tools at a stage in carrying out the second illustrative method spring, corresponding to the stage of the first illustrative method shown in FIG. 3;

FIG. 7 is a view ofa spring showing a loop made by carrying out the first illustrative method; and

FIG. 8 is a view of a spring showing a loop of the cross-over centre type.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The first illustrative machine is similar, except as hereinafter described, to that described in the specification of US. Pat. No. 3,662,778 with reference to the drawings which accompanied said specification and reference is hereby directed to said specification for a full description of the machine. In the following description parts of the illustrative machine are given the same reference number as the same parts of the aforesaid machine described in the aforementioned specification, where the parts are identical.

The first illustrative machine differs from the aforesaid machine described in the aforementioned specification in that it has different tools. The first illustrative machine comprises a first opening tool 702 (mounted in place of the opening tool denoted as 66 in the aforesaid specification) comprising a plate portion 704 a first, front, flat surface 706 of which is arranged to slide across a flat rear end surface 708 ofa spring holder 106 of the first illustrative machine and two parallel ribs 710 projecting rearwardly from the plate portion 704 leaving a parallel-sided groove 712 therebetween. A left hand (viewing FIG. 1) end portion of the plate portion 704 is tapered and left hand (viewing FIG. 1) end portions of the ribs 710 form with the tapered portion of the plate portion a continuous smooth second surface 713 of the first tool 702 meeting the first surface 706 at a sharp leading edge 714 to provide a leading end portion of the first tool. The groove 712 intersects the second surface 713 to produce a slot in the second surface.

The first illustrative machine also comprises a second, anvil tool 716 (mounted in place of the tool of the aforesaid machine described in the aforementioned specification). The anvil tool 716 comprises a metal slab portion 718 slidable along the groove 712 in the opening tool, the slab portion 718 having an inner (left hand viewing FIG. 1) end surface 720 extending at right angles to the first surface 706 of the opening tool 702. The anvil tool 716 also comprises an outer end portion having a curved, forward portion.

The first illustrative machine also comprises a third tool 722 (mounted in place of the hammer tool 82 of the aforesaid machine described in the aforementioned specification). The third tool 722 comprises a mounting block 724 in which are bored two parallel holes and two operating members 726, 728 each comprising a shaft portion 730 received in an associated one of the holes in the block 724 and clamped in place: the relative positions of the members 726, 728 towards and away from the block 724 can thus be independently adjusted by clamping the respective shaft portions 730 in appropriate positions. The operative members 726, 728 are arranged to be clamped with two adjacent flat faces 732 (FIG. parallel and spaced apart a sufficient distance to slidingly receive the slab portion 718 of the second tool therebetween. The member 726 has an inner (right hand viewing FIG. 1) end face 734 parallel with the end surface 720 of the slab portion 718 and the member 728 has a hooked inner (right hand viewing FIG. 1) end portion 736 (see also FIG. 5).

In the operation of the first illustrative machine in carrying out the first illustrative method the tools are initially at rest in the positions in which they are shown in FIG. 1. A spring 738 is slid into a bore 740 in the holder 106 (the holder 106 having been selected such that the bore 740 is of a diameter such that the spring is a sliding fit therein) and pushed into the bore until a rear end portion of the spring engages a flat front eating face ofa locating head 118 of the first illustrative machine. A projection 144 projects forwardly from the locating face and the spring 738 is rotated in the bore 740 until the cut end of the wire of the spring engages the projection 144 thus to locate the cut end in a desired position (the position of the projection 144 being adjusted as mentioned in the aforesaid specification). When the spring 738 has been accurately located the machine is tripped by an operator e.g. by operation of a treadle, to swing the locating head 118 clear (to its dash line position in FIG. 1) and to slide the opening tool 702 inwardly transversely of the spring holder 106 so that the front surface 706 of the plate portion 704 slides over the rear'surface 708 of the holder 106. The leading edge 714 enters between one of the coils of the spring 738 projecting from the holder 106 and another of the coils which remains within the bore 740 of the spring holder 106. The opening tool 702 is advanced to separate the projecting coil from the remainder of the spring and bend it (see FIG. 2) to form a loop 742.

Next, in the operation of the first illustrative machine in carrying out the first illustrative method, the anvil tool 716 is advanced from its retracted position (in which it is shown in FIG. 1 along the groove 712 in the opening tool 702 until the leading end surface 720 of the slab portion 718 engages the loop 742 separated by the opening tool 702 (see FIG. 3) and bends it further.

The third tool 722 is likewise moved transversely of the holder 106 towards the anvil tool 716 and the leading end face 734 of the first member 726 of the third tool 722 engages the wire of the loop 742 near the cut end while the end portion 736 of the second member 728 of the third tool 722 also engages wire of the loop 742 but further from the cut end (see FIGS. 4 and 5). As the third tool 722 is advanced the members 726, 728 pass on either side of the slab portion 718 and bend the loop 742 about the end surface 720 of the anvil tool 716, the anvil tool 716 being maintained in position. The end portion 736 of the member 728 acts to maintain the loop 742 in position (the loop being held by the hooked portion, see FIGS. 4 and 5) while the end face 734 of the member 728 bends the wire of the loop 742, thus to impart a permanent set to the wire of the spring to maintain the loop in a desired position. The operation of the opening tool 702 is such that the tool 702 remains in position across the end of the bore 740 (retaining the spring 738 in the bore 740) until it engaged by the third tool 722 and pushed back towards its original position the power pushing it inwardly having been removed: subsequently the tool 702 is withdrawn to the position in which it is shown in'FIG. 1 under power.

When the loop 738 has been set the tools 702, 716 and 722 are fully retracted to the positions in which they are shown in FIG. 1 and the locating head 118 is returned to its full line position (see FIG. 1). Where the first illustrative machine is operating on a spring of large diameter the outer end portion of the anvil tool 716 may travel inwardly of the wire of the coils and as the tool 716 is retracted the forward portion 715 may engage the wire of the spring; the forward portion 715 is curved to facilitate sliding of the forward portion 715 of the anvil tool 716 over wire of the spring. The spring 738 is finally removed. In carrying out the first illustrative method the loop 742 formed is of the type known as a German loop (see FIG. 7).

As described in the aforesaid machine described in the aforementioned specification, the innermost positions of the tools 702, 716, 722 may be adjusted so that a variety of different springs may be operated upon and, as hereinbefore mentioned, the relative positions of the members 726, 728 may likewise be adjusted. For springs of different outside diameters spring holders having different bore diameters are needed. To render removal of a looped spring from the holder more easy a modified type of spring holder having a bore of square (instead of circular) cross-section may be used.

It has been found that in using the first illustrative machine to loop springs of small diameter, for instance springs of 3/16 of an inch diameter, that a bend is imparted to the wire of the spring at the uppermost part of the loop formed. A bend in the wire at that point is not a desirable feature and it was found that this could be avoided by reversing members 726 and 728 so that the hooked inner end portion 736 of chamber 728 engages the wire of the loop 742 nearer to the end of the wire than does member 726.

The second illustrative machine (see FIG. 6) is similar to the first illustrative machine except that the anvil tool 716 is replaced by an anvil tool 744 having an inclined inner end surface 745 (instead of the end surface 720) meeting a flat surface 748 which runs in the groove 712 in the opening tool 702 parallel to the flat surface 706 at an acute angle. In carrying out the second illustrative method the second illustrative machine operates in the same way as does the first illustrative machine in carrying out the first illustrative method and a German loop is formed. However, by adjustment of the second illustrative machine it is possible to extend the loop slightly so that, where a loop has already been made on the opposite end of the spring, the distance between the loops may be pre-selected.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

1. A machine for forming a German loop on an end portion of a coil spring comprising: a support for the spring; a first tool movable transversely of the support for initially separating a coil at an end portion of the spring from the remainder of the spring; a second tool movable transversely of the support for further separating the end portion coil; and a third tool having only first and second portions spaced from each other and movable transversely of the support to engage the separated coil and to pass on eitehr side of the second tool for permanently setting the coil as a German loop extending from a coil of the remainder of the spring.

2. A machine as in claim 1 wherein one portion of the third tool has a hooked end portion for engaging and holding the separated coil.

3. A method of forming a German loop at an end portion of a coil spring comprising a spring with a portion of the spring projecting from support means, moving a first tool transversely of the support means to initially separate one or more coils or parts of coils of the projecting portion of the spring from the remainder of the spring to form a loop, moving a second tool transversely of the support means to further separate the loop from the remainder of the spring and moving a third tool having only first and second portions spaced apart from each other towards the second tool to press the loop between the second and third tools with a portion of the third tool engaging the loop and passing on either side of the second tool to impart a permanent set to the loop for extending as a German loop from a coil of the remainder of the spring.

4. A method as in claim 3 additionally comprising holding the loop with a portion of the third tool simultaneously with engaging the loop with the portion.

zg g g UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,782,425 Dated Terence James Leonard Clarke, Robert Charles Quarmby Inventofls) and Philip Michael Lett It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the claims:

Claim 3, Column 5, Line 7, after comprising and before a, insert --supporting-- Signed and sealed this 16th day of April (SEAL) d Attest:

EDWARD M .FLETCHERJR. c. MARSHALL DANN Attesting Officer Commissioner of Patents 

1. A machine for forming a German loop on an end portion of a coil spring comprising: a support for the spring; a first tool movable transversely of the support for initially separating a coil at an end portion of the spring from the remainder of the spring; a second tool movable transversely of the support for further separating the end portion coil; and a third tool having only first and second portions spaced from each other and movable transversely of the support to engage the separated coil and to pass on either side of the second tool for permanently setting the coil as a German loop extending from a coil of the remainder of the spring.
 2. A machine as in claim 1 wherein one portion of the third tool has a hooked end portion for engaging and holding the separated coil.
 3. A method of forming a German loop at an end portion of a coil spring comprising supporting a spring with a portion of the spring projecting from support means, moving a first tool transversely of the support means to initially separate one or more coils or parts of coils of the projecting portion of the spring from the remainder of the spring to form a loop, moving a second tool transversely of the support means to further separate the loop from the remainder of the spring and moving a third tool having only first and second portions spaced apart from each other towards the second tool to press the loop between the second and third tools with a portion of the third tool engaging the loop and passing on either side of the second tool to impart a permanent set to the loop for extending as a German loop from a coil of the remainder of the spring.
 4. A method as in claim 3 additionally comprising holding the loop with a portion of the third tool simultaneously with engaging the loop with the portion. 